Sandy soils can show poor water use by crops. There are around 5 million hectares of sandy soils in Australia’s low-medium rainfall southern region. Growers see poor crop performance even with residual subsoil water at harvest.
To date, options to improve sandy soils are either:
- Mitigation: lower-cost, annual activities. Techniques include furrow management, seeding strategies, wetting agents, nutrient placement and crop choice.
- Amelioration: higher-cost options that aim to change the soil profile. Techniques include deep placement of amendments, claying, spading and inversion.
A new GRDC project will extend existing research. Water use alone is not the cause of low yield. Other factors include:
- physical and chemical barriers to root growth
- nutrient supply and biological cycling
- poor establishment,
- heat stress and evaporation.
The interactions are complex, spatially variable, and seasonal. The project aims to find ways to reliably increase production on sandy soils in the southern region.
So far, the known issues and mitigation strategies have been compiled. Findings from WA research on non-wetting soils could be applied. The next steps are to identify the:
- main soil issues (physical, chemical and biological) limiting roots and crop water use
- most effective ways to manage the causes of poor performance.
Field activities across the Southern region:
- Six new field trials:
- Lameroo (SA), Ouyen (VIC), Yenda (NSW), Eyre Peninsula (SA), Northern Yorke (SA), Carwarp (VIC)
- Monitoring three established trials:
- Brimpton Lake, Karoonda, and Cadgee (all SA).
Lynne Macdonald, CSIRO